Preparation of cation active resins



Patented Feb. 7, 1950 2,497,054 ranrma'rrou-or carrou ao'rrvn RESINS Harold no,

ican .Cyanamnl Company, corporationoi-Mame Application September 4,1946, iSerial-No. 694,817

No Drawing.

5 Claims.

This invention relates to .cation thetic resins and more particularly, to cationic synthetic resins prepared from 4,4-.dihydr.oxydiphenyl sulfone, formaldehyde .and an alkaline sulfiting agent, to .methods of preparing such resins, and to the .use of the resins for the .removalof cations from, .or the exohangeof .cat: ions in, liquid .media.

Water-soluble condensation .products of a3- dihydroxydiphenyl .sulione, formaldehyde and sodium .sulfite or similar sulfiting .agent are known and their .use .as tanning agents is .disclosed in such patents as .No. 2,036,161 and No. 2,320,678.

I vhave c e ed that water-insoluble .mate- 15 rials suitable .for -the;;removal of cations from liquids may be prepared by bringing .aboutreaction between .A -dihydroxydiphenyl sulione, formaldehyde and an. lkaline sulfiting agent.

The {present invention will .be described .in greater detail in conjunction with theiollowing specific example in which the proportions .are given in parts by weight. This example is merely illustrative, and it is not intended that the scope of theinvention be restricted to .the

details therein set .forth.

Example 125 parts of 4,4'-dihydroxydiphenyl sulfone (0.5 mol) I 63 parts of sodium sulfite (0.5 mol) 202.5 parts of 37% Jiormalin (2.5 mols) The ingredients are charged into a reaction vessel fitted with a reflux condenser and mechanical means for agitating. The batch :is heated under reflux for about 3 .hours until a clear viscous syrup is obtained.

.The syrup is precured for about 16 hours at 100 C. and finally'cured for 16 hours at 150 C. The cured resin is then cooled, ground and evaluated. It has a capacity of 13.8 'kilograins of calcium carbonate per cubic foot of resin.

Any alkaline sulfiting agent may be used .in place of the sodium sulfite of the example. Such sulfiting agents include other alkali metal sulfites, for exampleapotassium sulfite, alkali metal bisulfites, "for. example, sodium metabisulfite, sodium bisulfite 1iquor,-potassium bisulfite, etc. It will be apparent that mixtures of two or more of the sulflting agents of the type listed above may be utilized in place of any single agent.

I prefer using a molar ratio of formaldehyde to 4,4'-dihydroxydiphenyl sulfone of about 5:1, but the invention is in no sense limited to this particular proportion. More formaldehyde generally produces a resin of no higher capacity while less formaldehyde may result in a more water-soluble product. In general, ratios of from active syn Cos-Cob, Conn., assignor tcAmer- New York, N. Y., a

4:1 to 10:1, formaldehyde to phenolic compound, may be utilized.

--I'-prefer to react phenolic compound and the sulfiting agent 'ina '-1:1 molar ratio. If more sulfiting agent-is used the resulting resin has a tendency to swell badly, and if less sulfiting agent is used the resulting resin may have a lower exchange capacity. However, the inven 1 proportion.

- At least one molar proportion of formaldehyde 'must be reacted with the phenolic compound before'it is sulfited since presumably only one'of' the -methylol groups is sulfited in the final resin. -Evidence for this 'isthe recovery of one mol of sodium hydroxide'for each moi of 4:4- dihydroxydiphe'nyl *sulfnne reacted. Accordingly,'itis possible withinthe'scope of the present invention to condense the '4,4'-dihydroxydipheny'l sulfo'ne, formaldehyde and agent'simultaneously or to condense the phenolic compoun'd'with the excess of formaldehyde and treat 'the "resuiting condensation product with the .sulfiting agent. "If desired, something less thanthe'total'amomt of formaldehyde'but at least anxequimolar quantity thereof may be precon'densed'with the phenolic compound, the re sulting condensation product treated with a sulfiting agent, and the sulfited product then ".n resinified with the remainder of the formaldehyde.

I have found it best to cure the cation exchange resins of the present invention at high temperatures, i. 'e. about '125-150 C. If the 5 resin is finally cured at a lower temperature it has a tendency to swell. It is desirable to precure the resins at a lower temperature, about 100 C., but grinding the pre-cured' resin before final curing has no particular advantage in that the resin so obtained does not have as good .a capacity as one which is not ground between the pre-curing and 'final curing steps.

A resin of higher capacity may be obtained if the free alkalinity of the reaction mixture, which is due vto the molar equivalent of sodium hydroxide liberated in the reaction for every mol of sulfiting agent used, is reduced. This.

may/be accomplished by neutralization with an acid wash. .The alkalinity may also be reduced byntilizing ;a mixture of bisulfite and sulfite as the :sulfiting agent.

.Itis certain'that the sulfurbf at sulfite group is attached mean-aliphatic carbon aimn in the final resin; no nuclear sulfonation takes place under the conditions of the reaction.

While I-do not wish to be limited to any particular theory as to mechanism of the formation of the cationic synthetic resins of the present 60 invention, 1 believe that the reaction which oction is "in no sense restrictedto this particular curs may be represented schematically as follows: e

so, mono NsgSO; o, men

nonio- OHIOH on I H It is an advantage of the present invention that the granular, water-insoluble synthetic resins produced in accordance therewith are capable of exchanging cations in liquid media and of removing cations from liquid media. In this connection, my resinous materials may be used in admixture with other cation active materials or they. may be used alone. Furthermore, my resins may be applied before gelation to a suitable carrier such as diatomaceous earth, clay, charcoal, etc. In this way, the active resin is spread on the surface of a relatively inert material and one is thus enabled to employ a smaller quantity of resin than otherwise to obtain the same active area.

Resinous materials prepared according to my invention are useful in the removal of cations from fluid media, especially aqueous solutions. The resins may be used in the hydrogen-activated form to remove cations from solution bases, and they may also be employed as exchange materials in accordance with the principles applied tolthe use of the natural and synthetic zeolites. Thus, the resin maybe activated with a sodiumsalt such as sodi umfchloride and upon contactwith a solution containing calcium, magnesium or other cations, an'exchange of the latter ions for thesodiumions' takes place.

The activating solutions or regenerating solutions for myiresins. are dilute acid'solutions or dilute saltsolutions,.e. g., about'0.2%-l0% of suliuric acid, hydrochloric acid, sodiumchloride potassium chloride, etc. I T 7 To be suffic'ie'ntly insoluble for practical use;

inthe art oiwater purificatioma 'resin should have a sufiiciently' low solubility that it will not be dissolved away rapidly by the solution to be treated. Thus, water should not-dissolve more than about 1 part of resin in 1,000 parts of water when passed througha bed ofresin (after the first cycle comprising an activation, exhaustion and reactivation of the resin).

It is preferable to grind and screen the resins to a particle size of from about 8-60 mesh. Use of larger particles causes channeling, and smaller reducing the cation exchange efiiciency of the material.

My resinous materials are useful for a wide variety of purposes. Some of the uses which may be mentioned by way'of example are: water puri fication; purification of aqueous solutions containing sugar, including sugar juices; purification of water from lead pipes; removal of heavy metal ions from food, beverages .and pharmaceutical products; decolorization of solutions containing coloring matters, etc. My condensation products may also be employed to recover valuable metal cations from dilute solutions, e. g., gold from sea water, chromium from chrome tanning liquors,

silver from photographicpaths, etc. Another imand the amines, e. g., triethyl amine, methyl amine, etc., from fluid media, either dissolved in a liquid or from vapors.

I claim: 1. A granular, water-insoluble synthetic resinous material having a capacity for exchanging cations in liquid media and obtained by a. process which comprises bringing about reaction between '4,'4 '-dihydroxydiphenyl sulfone, formaldehyde and an alkaline sulfiting agent by heating, until formation of a viscous syrup occurs, curing the particles of resin have been found to pack, thus syrup by heating at about -150 C., and granulating the cured material to a particle size of from 8 to 60 mesh, relative molar proportions of of formaldehyde to 4,4'-dihydroxydiphenyl sulfone being from 4:1 to 10:1- and of 4,4'-dihy-- droxydiphenyl sulf one to sulfiting agent being 1:1. 3.-A process of removing cations from liquid media which comprises bringing the liquid media into contact with the granular, water-insoluble synthetic resinous material of claim 1 and separatingsaid liquid media from said material.

4. A process of preparing a granular, waterinsoluble synthetic resinous material'having a capacity for exchanging 'cations in liq'uid media which includes the steps of heating 4,4-dihydroxydiphenyl sulfone with at least an equimolar proportion of formaldehyde, reacting the con-. densation product with an alkaline sulfitingagent' by heating and curing, the reaction product by heating at about 125 0., relative molar proportions of formaldehyde to 4,4'-dihydroxydiphenyl sulfone being from 4:1 to 10:1and of 4,4-

dihydroxydiphenyl sulfone to sulfiting agent be-.

ing 1:1.

,5. A process of preparing a granular, Water-insoluble synthetic resinous material having a capacity for exchanging cations 'in liquid media which comprises simultaneously condensing 4,4-

dihydroxydiphenyl sulfone, formaldehyde and an alkaline sulfiting agent by heating and curing the condensation product by heating at about 125150 0., relative molar proportions of formaldehyde to 4,4'-dihydroxydiphenyl sulfone being from 4:1 to 10:1 and of 4,4'-dihydroxydiphenyl' sulfone to sulfiting agent being 1:1.

HAROLD M. DAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 7 Date 2,228,159 ,Wassenegger et al. Jan. 7, 1941 2,285,750 Swain June 9, 1942 2,357,798 Niederhauser et al.' Sept. 12, 1944 2,372,233 Thurston 1 Mar. 27, 1945 

1. A GRANULAR, WATER-INSOLUBLE SYNTHETIC RESINOUS MATERIAL HAVING A CAPACITY FOR EXCHANGING CATIONS IN LIQUID MEDIA AND OBTAINED BY A PROCESS WHICH COMPRISES BRINGING ABOUT REACTION BETWEEN 4,4''-DIHYDROXYDIPHENYL SULFONE, FORMALDEHYDE AND AN ALKALINE SULFITING AGENT BY HEATING, UNTIL FORMATION OF A VISCOUS SYRUP OCCURS, CURING THE SYRUP BY HEATING AT ABOUT 125*-150*C., AND GRANULATING THE CURED MATERIAL TO A PARTICLE SIZE OF FROM 8 TO 60 MESH, RELATIVE MOLAR PROPORTIONS OF FORMALDEHYDE TO 4.4''-DIHYDROXYDIPHENYL SULFONE BEING FROM 4:1 TO 10:1 AND OF 4,4''-DIHYDROXYDIPHENYL SULFONE TO SULFITING AGENT BEING 1:1. 